Human Respiratory and Cardiac Systems

Respiratory and
Cardiac Systems

Table of Contents
• Introduction
• Structure of arteries, veins and capillaries
• Structure of the heart and cardiac cycle
• Electrical activity of the heart during a heartbeat
• Cardiac output and importance of the value
• Conclusion
• References

Introduction
• Respiratory system refers to the set of organs which allows an
individual to breathe and exchange oxygen & carbon dioxide
throughout the body.
• Cardiac system consist heart and circulatory system to facilitate flow
of blood to organs, tissues and cells in human body.

Structure of arteries, veins and capillaries
• Arteries are larger and walls are thicker compare to veins because
they carry the blood directly from heart.
• Pressure on arteries, greater than the veins. Blood pressure on the
vein is less than the arteries because veins are draining blood from
capillaries bed.

Structure of the heart and cardiac cycle
• Cardiac cycle is sequence of events which occurs when heart beats.
• There are two phases diastole and systole phase. Diastole phase,
heart ventricles are relaxed, heart fills with the blood.

Electrical activity of the heart during a
heartbeat
• Ventricles and atria work together, alternating relaxing and
contracting to pump blood through the heart.
• Electrical system of heart is power source which makes it possible.
• Electrical activity spreads through walls of atria and causes contract.
The SA node sets rate and rhythm of heartbeat.

Cardiac output and importance of the value
Cardiac output is volume of blood heart pumps per minute. Cardiac
output is calculated, multiplying stroke volume by heart rate.
Stroke volume is calculated by preload, afterload and contractility.
Normal range for the cardiac output is 4-8 L/min but it also depend on
metabolic needs of body.

Conclusion
The above report has been concluded that human respiratory and
cardiac system is very important for humans. Respiratory system
helps in gaseous exchange and ventilation which helps to respire
humans. However, smoking is harmful for an individual as it
damages lungs and may results into lung cancer.

References
Martin, D. C. C. and Oates, J. D., ResMed Ltd, 2014. Systems,
methods, and/or apparatuses for non-invasive monitoring of
respiratory parameters in sleep disordered breathing. U.S. Patent
8,646,447.
Trinder, J. and Nicholas, C. L., 2016. Respiratory and cardiac activity
during sleep onset. In Sleep Apnea (pp. 81-96). CRC Press.

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